1. Field of the Invention
The present invention relates to telecommunication networks, and more specifically to a method and apparatus for sharing line bandwidth among virtual circuits in an asynchronous transfer mode (ATM) device.
2. Related Art
Asynchronous transfer mode (ATM) based networks generally contain several ATM devices (e.g., switches, edge routers) connected by communication paths. Each path is generally characterized by an amount of bandwidth (“line bandwidth”), which is shared by several virtual circuits as is well known in the relevant arts.
Such sharing needs to be implemented while meeting/balancing various requirements. For example, it is generally desirable that certain types of virtual circuits (e.g., of constant bit rate type) be provided higher priority than certain other types of virtual circuits (e.g., of available bit rate type). ATM standards may specify such priorities.
Another generally desirable feature is support for over-subscription. Over subscription generally refers to a situation in which the aggregate allocated bandwidth for all virtual circuits active on a path exceeds the line bandwidth of the path.
In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.